inferior cerebellar peduncle

Definition: large paired bundles of nerve fibers that develop on the posterolateral surfaces of the upper medulla, extend under the lateral recesses of the rhomboid fossa and curve upward into the cerebellum caudomedial to the middle cerebellar peduncle; composed of a larger (lateral) bundle, the restiform body [TA], and a small (medial) bundle, the juxtarestiform body [TA]. Fibers forming this composite bundle originate from spinal neurons and medullary relay nuclei. The largest constituent (restiform body) contains crossed fibers from the inferior olive; it also contains the posterior spinocerebellar tract and cerebellar projections from the lateral reticular nucleus, the accessory cuneate nucleus, the paramedian reticular nuclei, the perihypoglossal nuclei, and other nuclei. Vestibulocerebellar fibers are placed medially in the inferior cerebellar peduncle and are separately identified as the juxtarestiform body.